We've had a Bosch for a long time and it's been very quiet and reliable. The gasket is worn away and there are a few other issues with wear and tear (soap dispenser doesn't always open, etc.), and I'm trying to decide about repairing/replacing.
I always look at Consumer Reports, to get an overview of repair records form a lot of people, as well as overall satisfaction. They often give you the "best deal" sort of evaluation too. They also test in their own labs.
One thing I learned from years of using CR is that manufacturers often have specific model numbers for certain retailers, so if you go from store to store, the model numbers don't match exactly. Sometimes CR can help you figure that out, so that the model you buy at Sears is so close to the model you buy at Home Depot (even though the numbers are different), you know what's equivalent.
For me, having a dishwasher that heats the water more than the temp of my water heater makes sense - I don't want to pay for super-heated water for the whole house including my sinks, when I might want it for really dirty dishes. I also rarely use the dry cycle - I save electricity and emit more humidity into the winter air by letting things air dry - so I want options. My old dishwasher has settings for power scrub and things like that that I've never used.
My repair guy said to really rinse all the dishes of food residue because it gets stuck in the vents. We had been running through some jars for recycling when we had room, and he said not to, because the glue from the labels and some of the paper was getting stuck in the washing arm and clogging the holes. So that's kind of a pain but I don't think it's unique to any one brand of dishwasher.
I agree with you about a 1 decibel difference. So I'd look at repair records and energy efficiency - if your $200 difference is going to save you a repair call or 3, or save energy over 5 years, it's worth it.